I don't know if you've already gotten a thousand responses to your question already, but here's my 2 cents:
Sounds like a classic case of round ligament pain. The ligaments stretch and ache a lot as your uterus expands. Mine were so bad for a couple of days I could hardly stand up straight or lie down flat. So I went to the doctor thinking I had a bladder infection or something was wrong and my doctor just said it was round ligament pain due to my uterus growing causing the ligaments to stretch. It's pretty painful and can sometimes be excruciating even though most stuff you read about round ligament pain says it's just a slight uncomfort or sharp pain that lasts for just a few minutes. For me it lasted 15 to 30 minutes at a time! Don't worry, all that pain means is your uterus is growing as your baby gets bigger. It's a good thing even though it hurts. Hang in there!